Rick Pauer, CCP's marketing manager, addressed the issue of mold shrinkage, pointing out that one of the problems with traditional vinyl ester tooling resins is postcure shrinkage that can lead to orange peel, fiber print or mold cracking.
offers high-temperature-resistant OptiPLUS polyester resins as a substitute.
Used for the fabrication of composite tooling via vacuum infusion, OptiPLUS resin chemistry is designed to counteract postcure shrinkage.
Styrene monomers are reacted in the presence of a catalyst, releasing a large amount of exothermic heat.
This heat drives up the rate of the initial cure, thereby reducing the amount of what CCP
calls residual cure that remains in the mold.
Residual cure, if substantial, can cause shrinkage as the mold is reheated during subsequent production runs.
reported that OptiPLUS resins contain a thermoplastic filler that has a positive coefficient of thermal expansion, which helps to offset shrinkage in the polyester as it cures.
"The three Vectorply materials were used to maximize flow [and] surface quality and for rapid bulking," Pauer
Although the room-temperature viscosity of OptiPLUS at 75°F/24°C is approximately 100 cps, shop temperatures exceeded 90°F/32°C on this particular day, so Pauer
estimated the viscosity at 75 to 80 cps, which shaved about eight minutes off the normal 24-minute mold-fill time.